Nook 1.2 emulator

I was able to build an emulator for Nook version 1.2. See my previous post for the prerequisites. Basically you need some utilities installed: smali, baksmali, unyaffs, and mkyaffs2image. You also need the Android SDK installed on your computer. Here are the steps: 1: download the nook 1.2 soft-root image from nookdevs. For the rest of this post I assume you have copied it into the directory ~/nook_dev/ and we will be working on it from there. 2. extract the bravo_update.dat, cd into it and extract root.tgz

mv bravo_update.dat bravo_update-1.2.tar.gz
tar xvzf bravo_update-1.2.tar.gz

3. extract root.tgz

cd Firmware_Update
tar xvzf root.tgz
cd root

4. cd into system/framework and unjar services.jar

cd system/framework/
jar xvf services.jar

5. disassemble the classes.dex file inside services.jar

baksmali classes.dex

6. vi out/com/android/server/ServerThread.smali search for a line that contains

if-lt v0, v1, :cond_309

delete that line. 7. reassemble out/ directory

smali out/

8. copy the new out.dex over the old classes.dex and re-jar services.jar

mv out.dex classes.dex
jar cvf services.jar classes.dex

Now we are going to build an android AVD, so we can extract a single file to use back in this system.

9. if your android SDK tools are in your path Run,

android

else find the android command and run it, or run it from eclipse. This starts the Android SDK and AVD Manager. To create a new AVD, click New... Name: nook Target: Android 1.5 Size: Skin: click Resolution, and fill in 488 x 944 click "Create AVD". Then click "Details" to see where it was created. It should be at ~/.android/avd/nook.avd 10. unyaffs the system.img and grab a file

cd ~/nook_dev/
mkdir sys_img
cd sys_img
cp ~/android-sdk-linux_86/platforms/android-3/images/system.img .
unyaffs system.img
cp lib/libaudioflinger.so ~/nook_dev/Firmware_Update/Firmware_Update/system/lib/libaudioflinger.so

11. re-create the system.img with the new audio file.

cd ~/nook_dev/Firmware_Update/Firmware_Update/
mkyaffs2image ./system/ system.img

this creates a new system.img 12. Sketchy step where you overwrite the good Android 1.5 platform system.img in your Android SDK with this new one.

mv ~/android-sdk-linux_86/platforms/android-3/images/system.img ~/android-sdk-linux_86/platforms/android-3/images/good.img 
cp ~/nook_dev/Firmware_Update/Firmware_Update/system.img ~/android-sdk-linux_86/platforms/android-3/images/system.img 

Remember to change this back later if you want to do non-nook related Android Development. 13. run the emulator!

emulator @nook -shell -show-kernel -verbose

How to Build a Nook emulator

This post will walk you through building an Android Emulator for the Nook step-by-step in Eclipse and via the command-line. These instructions are based on the original instructions located at the nookdevs website.

Pre-requisites:

1. You need to have Eclipse running with the Android SDK. More information on that can be found here.
2. I'm assuming you are developing in a Linux-ish environment. I'm using the amazing Ubuntu Lucid Lynx.
3. download and set up the following tools: smali, baksmali, unyaffs, yaffs2image.

How I Set Up the command-line tools:

smali and baksmali. Description from the developer's site:
"smali/baksmali is an assembler/disassembler for the dex format used by dalvik, Android's Java VM implementation".
1. Download them into your ~/bin/ directory.
2. "chmod +x" the wrapper scripts (smali and baksmali)
3. rename the jar files: smali.jar and baksmali.jar.

cd ~/bin/
wget http://smali.googlecode.com/files/smali-1.2.2.jar
wget http://smali.googlecode.com/files/baksmali-1.2.2.jar
wget http://smali.googlecode.com/files/baksmali
wget http://smali.googlecode.com/files/smali
mv baksmali-1.2.2.jar baksmali.jar
mv smali-1.2.2.jar smali.jar
chmod +x smali
chmod +x baksmali

unyaffs description: Unyaffs is a program to extract files from a yaffs file system image.
1. download unyaffs into your
~/bin; chmod +x unyaffs;

mkyaffs2image:
1. download mkyaffs2image. I downloaded the yaffs2-binary.tar, untarred it and copied yaffs2/utils/mkyaffs2image to my ~/bin/ and chmod +x it.

Okay we have the tools and our environment is ready!

1. I'm assuming you already have Eclipse set up and running with the Android Development Kit. Nook runs on the cupcake 1.5 platform of Android. So first we have to make sure that the Android 1.5 Platform is installed. Assuming you downloaded the Android SDK into your home directory, run:

$ ~/android-sdk-linux_86/tools/android

This will start the Android SDK and AVD Manager. Click on Installed Packages and look for SDK Platform 1.5. If you do not see it, click on Available Packages and download and install it.

2. Grab the original 1.0.0 image from bn.com (mirrored here: multiupload).

3.Run

$ dd if=signed_bravo_update.1.0.0.dat of=signed-bravo-update.1.0.0.tar.gz bs=1 skip=152

This takes a while. You now have signed-bravo-update.1.0.0.tar.gz

4.Uncompress the new file: signed-bravo-update.1.0.0.tar.gz

$ tar xzvf signed-bravo-update.1.0.0.tar.gz

Now you have the uncompressed folder Firmware_Update,

$ cd Firmware_Update

5. Rename bravo_update.dat to bravo_update.tar.gz and extract it.

$ mv bravo_update.dat bravo_update.tar.gz
$ tar xvzf bravo_update.tar.gz

This uncompresses another Firmware_Update folder, cd in to it.

$ cd Firmware_Update

if you pwd, you'll be in Firmware_Update/Firmware_Update

6. Extract root.tgz

$ tar xvzf root.tgz

this uncompresses a lot of stuff. All of the Android system image actually. Later we will re-compress the system folder to create the system.img

7. Extract system/framework/services.jar with your favorite unzip utility.
I did this from the GUI, right click on file and select "Extract here".
$ cd services

8. disassemble the file classes.dex with baksmai

$ baksmali classes.dex

This create out/

9. vi out/com/android/server/ServerThread.smali
delete the line

if-lt v0, v1, :cond_483

(for the vi-newbies, you can search in vi by typing a forward slash and typing in a phrase like "if\-lt", then type dd, to delete the line, and ":wq" to write the file and quit)

10. reassemble the file with

$ smali out

11. Replace the old classes.dex with this re-assembled file:

mv out.dex classes.dex

12. delete the old out/ directory and re-jar the contents of the services folder, but the not the services folder itself.
(I moved the META-INF folder and classes.dex out of the services directory and into the parent framework directory. Removed the empty services directory. Right clicked the classes.dex and selected "compress", and selected as name "services" and type as "jar" file, then I dragged the META-INF file onto the new services.jar. Yes, I know there is a better way, but I'm kind of new to jar files...)

Now we are going to build an android AVD, so we can extract a single file to use back in this system.

13. if your android SDK tools are in your path Run,

android

else find the android command and run it, or run it from eclipse.

This starts the Android SDK and AVD Manager. To create a new AVD, click New...
Name: nook
Target: Android 1.5
Size:
Skin: click Resolution, and fill in 488 x 944
click "Create AVD".
Then click "Details" to see where it was created. It should be at ~/.android/avd/nook.avd

14. unyaffs the system.img and grab a file

cd ~/nook_dev/
mkdir sys_img
cd sys_img
cp ~/android-sdk-linux_86/platforms/android-3/images/system.img .
unyaffs system.img
cp lib/libaudioflinger.so ~/nook_dev/Firmware_Update/Firmware_Update/system/lib/libaudioflinger.so

15. re-create the system.img with the new audio file.

cd ~/nook_dev/Firmware_Update/Firmware_Update/
mkyaffs2image ./system/ system.img

this creates a new system.img

16. Sketchy step where you overwrite the good Android 1.5 platform system.img in your Android SDK with this new one.

mv ~/android-sdk-linux_86/platforms/android-3/images/system.img ~/android-sdk-linux_86/platforms/android-3/images/good.img 
cp ~/nook_dev/Firmware_Update/Firmware_Update/system.img ~/android-sdk-linux_86/platforms/android-3/images/system.img 

Remember to change this back later if you want to do non-nook related Android Development.

17. run the emulator!

emulator @nook -shell -show-kernel -verbose

Moving with Eclipse to a new workstation

The hard drive on my laptop started clicking quite ominously, so I figured it was time to order a new hard drive. I backed up my photos to the cloud (Flickr and Picasa) and backed up all my music and docs to Dropbox and Google Docs and waited for the new hard drive to arrive. Files are files: you just need to keep a regular backup; and email already lives in the cloud. That leaves my development environment. Here are the steps I've followed to move my development set up to a new computer. 1. open up Synaptic and download Eclipse. There are several Eclipse packages available. I selected the big Eclipse package which includes the JDT (Java Developer Tools) and PDE (plug-in development tools). I've had trouble before when I selected one of the smaller eclipse packages and tried to add the plug-ins I needed separately. 2. Download or copy over the Android SDK. 3. Put the Android SDK tools directory in my PATH in .bashrc b. then type 'bash', so the new .bashrc takes effect. c. type 'adb', to make sure the android SDK tools are in my PATH. 4. open up Eclipse and go to Help->Install New Software... click "add" to add a new tools depository, and add the android developer tools repository: https://dl-ssl.google.com/android/eclipse/. b. once the new depository is loaded, select the Android Developer Tools and Android DDMS and wait for Eclipse to download and install them. 5. moved my private signing key over. 6. moved over my projects and imported them through File->Import... ->Existing Projects into Workspace. b. if you get any errors, try right clicking on the project and select Android Tools->Fix Project Properties 7. Export an app and sign it with the key you moved over. (this is the scary part, if you lose the signing key you used to originally sign your app, you will not be able to provide any more updates to your app in the Android Market!) a. File->Export ... Android->Export Android Application --> select the project you want to Export --> Use existing keystore, (click location to locate it.) type in your password.... 8. Plug your dev phone into your workstation and install the app. a. adb install -r /path/to/YourApp.apk Whoo Hoo! The development environment (for android at least) is all moved over.

Updating my android g1 phone to cyanogen 4.2.15.1 with Danger SPL

Tonight cyanogen is releasing 5.0.7 of the cyanogenmod. This is a modified ROM for android phones, that will finally allow g1 phone users like myself to run most of the latest android apps on our phones. It will add most of the Android Eclair functionality to older android phones, except for Live Wallpapers, but I didn't really see myself using any live wallpapers anyway. The one catch is that the new ROM is too big to fit inside the G1's tiny internal memory. The G1 has 64 MB of room for ROMs, and according to Cyanogen no matter how he tried to squeeze the ROM 64 MB was still 4 MB too small. So in order to load the new ROM with the eclair goodies, you need to use an SPL (second program loader), to load the ROM. More info on the Danger SPL. So in anticipation of tonight's release, I am installing the Danger SPL on my phone. The danger spl how to at cyanogenmod.com says that the pre-requisites are a rooted G1/Dream phone (check) and a compatible radio, with links to the radio images. So I downloaded the radios, but nowhere in the rest of the article did it mention what to do with the radio images. I was worried, but then I realized you just need to have one of the radios currently on your phone or you need to install one of the images I downloaded. After searching the interweb for how to check which radio is installed on your phone, I found this article, which says look in your phone under: Settings->About Phone->Baseband version, the last part of the number is your radio version. In my case its 2.22.19.26I, which is compatible! So on to updating the ROM!

Non-destructibly upgrade your android app's database

So your android app is out in the wild with thousands of Happy Users and the Happy Users are begging and pleading for a new feature that requires a new field in your database. However, the aforementioned Happy Users, would quickly turn to Unhappy Users if your next upgrade wiped their data when it restructured the app's database. What to do? Here's how I upgraded my app's Database schema, while preserving all of the user's data. First of all, I use a DatabaseHelper class (that extends SQLiteOpenHelper) that performs some of the basic database needs (create, upgrade). The function we will concentrate on in this post is onUpgrade(). This function is called when the database version, represent with the constant DATABASE_VERSION is changed. Most barebones implementation of this function call will simply drop the app's tables and recreate them with a call to onCreate():

public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    ...
    db.execSQL("DROP TABLE IF EXISTS albums");
    onCreate(db);
}

However, this approach will destroy all of your user's data, (ie the entire 2500+ CD collection they painstakingly entered with the soft keybard--if this were the case perhaps you should add a barcode scanner intent, alas, back to the story.) Which results in a Very Unhappy User (hereafter VUU). The solution, is to check for the app's Database Version and make a call to our friend ALTER TABLE, like so.

public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
   if(oldVersion == 2) {
          db.execSQL("ALTER TABLE albums ADD COLUMN hip_again integer");
   } else {
         ...
        db.execSQL("DROP TABLE IF EXISTS albums");
        onCreate(db);
  }

}

There! Now your user's can flag their old CD's with the shifting tides of what's hip. Also note that should add the column in the onCreate method. So that Happy Users of the Future (hereafter HUF), will also have the field available to them:

private static final String DATABASE_CREATE =
          "create table albums (_id integer primary key autoincrement, "
          ...
          + "hip_again integer);";

@Override
public void onCreate(SQLiteDatabase db) {
                 db.execSQL(DATABASE_CREATE);
}

One final thing is to increment the constant DATABASE_VERSION, so that android will call onUpgrade() the next time the app is started:

private static final int DATABASE_VERSION = 3;

That's it.